Riot police have been deployed at Poland’s Constitutional Court amid an escalating stand-off between the government and the court’s top judges.

The row pits the government of Prime Minister Donald Tusk against his predecessors from the right-wing Law and Justice (PiS).

The police intervention came after Justice Minister Waldemar Żurek said he had requested stripping the court’s President Bogdan Święczkowski and Vice-President Bartłomiej Sochański of their immunity from prosecution to bring criminal charges against them.

Tusk has vowed to depoliticise the judiciary, and on Friday defended the move as PiS supporters gathered outside the court premises in Warsaw in protest.

Riot police were deployed to prevent any demonstrators from entering the court building.

In a social media post, the Constitutional Court wrote that the two judges the government wants to prosecute were still the legally appointed senior justices of the court.

“All persons participating in these actions are committing the crime of a coup d’etat,” it said.

In a social media post, Tusk wrote: “Restoring the rule of law is our duty. After years of Law and Justice’s lawlessness, this is a difficult, sometimes painful process that requires decisive action. There is no other way.”

President Karol Nawrocki, who is backed by PiS, ordered his plane be turned back to Warsaw on his way to Senegal to attend the Summer Youth Olympic Games.

The PiS-led government took office in 2015 and moved swiftly to appoint judges to the court to gain a majority there because the court has the power to decide on the legality of legislation.

Leading European courts – the European Court of Human Rights and the Court of Justice of the European Union – subsequently ruled the PiS majority had elected three of the judges improperly because they were duplicating positions that had been validly filled by the previous parliament.

The European courts ruled Poland’s Constitutional Court was no longer an “independent and impartial tribunal”, and Tusk’s government has used those rulings as a basis to stop publishing the tribunal’s rulings.

Tusk has failed to undo the PiS-era changes, partially because Nawrocki and his PiS-backed predecessor Andrzej Duda used their presidential vetoes to block his attempts.

Nawrocki has also refused to swear in five Constitutional Court judges elected by parliament since March on the grounds of alleged flaws in their selection procedure.

One of those judges, Anna Korwin-Piotrowska, has now been placed in temporary charge of the court.

Earlier this month, the Council of Europe’s advisory body on constitutional matters, the Venice Commission, said Nawrocki should swear-in the judges to allow them to sit on the court’s bench.

Justice Minister Żurek said Święczkowski and his vice-president should face criminal charges for not allowing the judges to adjudicate.

Some of Tusk’s supporters have accused him of failing to act decisively to reverse the PiS-era reforms.

Parliamentary elections are scheduled next year, and some see his move as an attempt to boost Tusk’s popularity among those voters.

But his actions have been criticised. In September, Tusk put forward a politician, Maciej Berek, a lawyer who served as a minister in his cabinet, as a judge candidate to the court.

Lawyer Marcin Matczak, a critic of the PiS-era judicial reform who has stated he considers Święczkowski to be the court’s worst president, said his suspension had no legal basis “for a million reasons”.

“Today’s action at the Constitutional Court, in my opinion, buries this body and the issue of the rule of law for two decades,” Prof Matczak wrote on social media.

“Images of armed police and legal interpretations according to which the minister of justice can remove the president of the Constitutional Court by decree will have a powerful, anti-rule of law backlash for years to come,” he added.